Dragon Project: Unwrapping issues
To get useful answers try to ask more focused questions.
It's not really clear where exactly you're stuck.

Feel free to post as many specific questions as you need, that's what this site is for :).



To adress small technical issues:


Repair non-manifold vertices (Select > All By Trait > Non Manifold)
Align the centerline more precisely (to mirror properly)
Correct Face orientation, as some are pointing the wrong way
To get rid of the rough polygonal look, you can use 2 levels of Subdivision Modifier.


To align the centerline enable Absolute Grid Snap.
You can use Scale tool to align more vertices at once.



Other tips


Use more circular edge loops on your model for easier unwrapping
Add more seams when possible, to limit the stretching
Learn more about making Normal Maps (you can learn a lot on this site)
Try the new Blender Remesher (since Blender 2.82)


For art critique, you can try BlenderArtists.com.



Repaired mesh with some simple materials and a new UV map.